/*
 * Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
 *
 *
 *
 *
 *
 *
 *
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 *
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 *
 *
 */

package com.sun.imageio.plugins.gif;

import java.io.IOException;
import java.util.Locale;
import java.util.Iterator;
import javax.imageio.ImageReader;
import javax.imageio.metadata.IIOMetadataFormat;
import javax.imageio.metadata.IIOMetadataFormatImpl;
import javax.imageio.spi.ImageReaderSpi;
import javax.imageio.stream.ImageInputStream;

public class GIFImageReaderSpi extends ImageReaderSpi {

  private static final String vendorName = "Oracle Corporation";

  private static final String version = "1.0";

  private static final String[] names = {"gif", "GIF"};

  private static final String[] suffixes = {"gif"};

  private static final String[] MIMETypes = {"image/gif"};

  private static final String readerClassName =
      "com.sun.imageio.plugins.gif.GIFImageReader";

  private static final String[] writerSpiNames = {
      "com.sun.imageio.plugins.gif.GIFImageWriterSpi"
  };

  public GIFImageReaderSpi() {
    super(vendorName,
        version,
        names,
        suffixes,
        MIMETypes,
        readerClassName,
        new Class[]{ImageInputStream.class},
        writerSpiNames,
        true,
        GIFStreamMetadata.nativeMetadataFormatName,
        "com.sun.imageio.plugins.gif.GIFStreamMetadataFormat",
        null, null,
        true,
        GIFImageMetadata.nativeMetadataFormatName,
        "com.sun.imageio.plugins.gif.GIFImageMetadataFormat",
        null, null
    );
  }

  public String getDescription(Locale locale) {
    return "Standard GIF image reader";
  }

  public boolean canDecodeInput(Object input) throws IOException {
    if (!(input instanceof ImageInputStream)) {
      return false;
    }

    ImageInputStream stream = (ImageInputStream) input;
    byte[] b = new byte[6];
    stream.mark();
    stream.readFully(b);
    stream.reset();

    return b[0] == 'G' && b[1] == 'I' && b[2] == 'F' && b[3] == '8' &&
        (b[4] == '7' || b[4] == '9') && b[5] == 'a';
  }

  public ImageReader createReaderInstance(Object extension) {
    return new GIFImageReader(this);
  }

}
